1. Field of the Invention
The present embodiments relate to semiconductor wafer processing equipment tools, and more particularly, carrier rings used in chambers. The chambers being for processing and transport of wafers.
2. Description of the Related Art
Plasma-enhanced chemical vapor deposition (PECVD) is a type of plasma deposition that is used to deposit thin films from a gas state (i.e., vapor) to a solid state on a substrate such as a wafer. PECVD systems convert a liquid precursor into a vapor precursor, which is delivered to a chamber. PECVD systems may include a vaporizer that vaporizes the liquid precursor in a controlled manner to generate the vapor precursor.
Chambers used for PECVD use ceramic pedestals for supporting the wafer during processing, which enables processing under high temperatures. One application is the deposition of ashable hardmasks (AHMs). AHMs are films used in semiconductor processing that may be removed by a technique referred to as “ashing.” In particular, AHMs are often used as etch stop layers. 193 nm or lower lithography schemes require these AHMs to have high etch selectivity to underlying dielectric or metal barrier layers.
Further, some chambers used to deposit AHM materials use a carrier ring to enable movement of the wafer between processing stations. If the carrier ring is not defined with geometries that account for exposure to deposition materials, the carrier ring in the chamber may produce particles during use, e.g., wafer lifting, and may require more trouble shooting during online processing and/or downtime due to more cleanings.
Existing methods of eliminating or reducing particle sources was believed to “optimize” wafer transport through the process module. “Optimizing” wafer transport included methods such as slowing down wafer motion and also ensuring carrier rings would not rattle as they were aligned to pedestals through alignment pins—method called “clocking”. “Clocking” pedestals is a laborious task and can lead to pedestal damage and slowing down wafer speeds is a throughput hit for end users.
It is in this context that inventions arise.